Most optical projection devices have a diffraction optical element (DOE), a holder, a collimating lens, a laser, a printed circuit board, and so on. The DOE, the holder, the collimating lens, and the printed circuit board are made of plastic materials. A space defined by the DOE, the holder, the collimating lens, and the printed circuit board is enclosed to avoid dust or debris entering into the interior of the optical projection device. Heat generated by the laser may not be dissipated out the enclosed space quickly and may affect the quality of the light projected out of the optical projection device.
Therefore, there is room for improvement in the art.